Ring retention in the homopolymerization of cyclic olefins by rhenium olefin metathesis catalysts

Abstract

Abstract The homogeneous catalyst system, Re(CO) 5 Cl/C 2 H 5 AlCl 2 , was found to promote the homopolymerization of cyclic olefins containing 5‐, 6‐, 7‐, and 8‐member rings to low‐molecular‐weight materials. The final compounds, which polymerize only at elevated temperatures, were found by nuclear magnetic resonance (NMR) and infrared (IR) studies to be totally saturated systems. Various bands in the IR spectra indicate that the ring systems are preserved and that the final products are made up of repeating 1,2‐, or a combination of 1,2‐ and isomerized single‐bond units. Although the active catalyst initially contains a coordinated carbene, a mechanism similar to that of polymerization by a Ziegler—Natta catalyst is proposed.